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    <title>单一按钮显示/隐藏</title>
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  <body>
    <div id="outer">
      <h2>播放列表...</h2>
      <ul>
        <li><a href="javascript:;">玩家之徒 - 蔡依林</a></li>
        <li><a href="javascript:;">原谅我就是这样的女生 - 戴佩妮</a></li>
        <li><a href="javascript:;">猜不透 - 丁当</a></li>
        <li><a href="javascript:;">自导自演 - 周杰伦</a></li>
        <li><a href="javascript:;">浪漫窝 - 弦子</a></li>
        <li><a href="javascript:;">流年 - 王菲</a></li>
      </ul>
    </div>
  </body>
</html>
